1. Field of the Invention
This invention relates generally to toilet valves, and more specifically to flush valves adapted for use in the tank of the toilet.
2. Description of the Prior Art
A typical toilet construction includes a toilet bowl, and a toilet tank which is initially filled through a fill valve. A flush valve is mounted in the bottom of the tank and is operable to release the water in the toilet tank to flush the toilet bowl.
In the past, flush valves have been constructed in a one-piece configuration with a valve seat having a central channel extending along a first axis and a valve elbow having an overflow tube extending along a second axis. A lateral passage provided fluid communication between the overflow tube of the elbow and the central channel of the seat. A flapper valve has been pivotal on the elbow and operable with respect to an opening on the seat to open and close the valve.
Initially, the opening in the valve seat was defined in a plane perpendicular to the axis of the valve seat and parallel to the bottom of the tank. This configuration provided the best loading of the flapper valve in the closed state. The one-piece construction was formed as a brass casting.
As the cost of castings increased, the industry began to look to injection molding for its economies of scale. Improving on the one-piece construction, injection molding could only be achieved using a core pin to define the lateral passage between the valve seat and the valve elbow. Lateral removal of this core pin required that the opening into the valve seat be canted from the prior perpendicular relationship with the axis of the seat. By canting the opening, the core pin, which was necessary to define the lateral channel, could be both inserted and removed through the opening. This process greatly reduced the unit cost of the product, but this was achieved only with the disadvantages associated with a candid valve seat and a generally reduced magnitude of flow. This magnitude of flow was dependent upon the size of the lateral channel which was necessarily limited by the size of the cord pin which could be inserted and removed through the candid opening.
In accordance with the present invention, a flush valve is provided with the economies of scale resulting from injection molding, along with a perpendicular valve opening providing uniform valve loading, and an enlarged lateral channel facilitating a higher flush rate.
The flush valve is constructed in two portions, a valve seat having a first sleeve in a valve opening having a second sleeve registerable with the first sleeve to create the lateral (passage). During the injection molding of the valve seat, a cord pin defining the first sleeve is removable, not through the valve opening, but laterally of the valve seat. Similarly, a cord pin defining the second sleeve in the injection molding of the valve elbow can also be removed laterally. In a final step achieving a one-piece construction, the second sleeve is inserted into the first sleeve in a friction fit relationship to define the lateral passage. Since the size of this passage is not dependent upon the size of the valve opening, it can be made larger thereby increasing the flush volume. Also, since it is not necessary to insert or remove a cord pin through opening, the opening can be formed in its preferred perpendicular relationship with the axis of the seat to provide for substantial uniform valve loading.
These and other features and advantages of the invention will be better understood with a discussion of preferred embodiments and reference to the associated drawings.